Question

I am trying to select some data in the following manner:

SELECT column
FROM table
WHERE a = a1
AND (b = b1 OR b = b2 OR b = b3);

What I want it to do is if b is not equal to b1, check if b=b2. However, if b=b1, do not check other conditions.
The result of this select statement must be only one entry. However, in the statement I have no, it checks all of the three conditions and sometimes returns multiple rows. Again, I would like it to stop checking if the condition is true.

Any ideas on how could this be implemented? I tried case but it did not work out…

Thank you in advance!

EDIT
Here is an actual query i am trying to run.

INSERT INTO shipment_flights 
    (airlinename, flt_no, flt_date, destination, phone, depttime, arrivaltime, pcs, weight)
SELECT st.airlinename, flightno, flightdate, destination,     
(SELECT phone 
FROM carrierlocations 
WHERE carriers_carrierid = (select carrierid from carriers where airlinename = st.airlinename) 
AND (city = destination OR (city != destination AND
    city = (SELECT city FROM airports WHERE iataid = 
            (SELECT airports_iataid FROM ratelegs 
                WHERE shipments_shipid = c.shipments_shipid))
                ))) phone, 
depttime, arrivaltime, sum(linepcs), sum(lineweight)
FROM segment_times st
    JOIN contents2flights c2f 
        ON st.flightid = c2f.segments_flights_flightid 
        AND st.segmentid = c2f.segments_segmentid 
    JOIN contents c 
        ON c.lineno = c2f.contents_lineno 
        AND c.shipments_shipid = c2f.contents_shipments_shipid

WHERE c.shipments_shipid = var_shipid
GROUP BY flightid
ORDER BY flightdate, depttime;

Here is a sample output:

airlinename         flt_no  flt_date        destination    phone         pcs   weight
Everts Air Alaska   CH1     2008-02-20      Hughes         9074502351    24    2121

The query inserts bunch of flight data into temporary table. What I am having trouble with is getting a phone number for a location. This part is as follows:

(SELECT phone 
FROM carrierlocations 
WHERE carriers_carrierid = (select carrierid from carriers where airlinename = st.airlinename) 
AND (city = destination OR (city != destination AND
    city = (SELECT city FROM airports WHERE iataid = 
            (SELECT airports_iataid FROM ratelegs 
                WHERE shipments_shipid = c.shipments_shipid))))) phone

In the query advised by Amit Bhargava, I get the right result only if there is one row in the temporary table. If there are more, it throws an error in the selecting phone part.

“Error Code: 1242. Subquery returns more than 1 row”

Answer 1

Please try the following. Not the most elegant solution, but it should work.

SELECT column
FROM table
WHERE a = a1
AND (b = b1 OR (b != b1 AND (b = b2 OR (b != b2 AND b = b3))))